Electronic component modules with a number of multilayered circuit carriers are known. These are produced, for example, by LTCC (Low Temperature Cofired Ceramics), which represents an efficient technology for producing ceramic circuit carriers from multiple individual layers. For this, ceramic unsintered green sheets are provided with openings for the electrical plated-through connections by punching out, the openings are filled with electrically conductive paste and the sheets are provided with planar conducting structures on their surface by the screen printing process. Numerous of these individual layers may be subsequently laminated one on top of the other and sintered at a relatively low temperature. The process produces multilayered, buried layout structures that can be used for the integration of passive circuit elements. In addition, this process can be used to create layout structures that have very good radiofrequency properties, are hermetically sealed and have good thermal resistance. With these properties, LTCC technology is suitable for applications in adverse environments, for example for sensors, in radio-frequency technology, for example in the mobile communications and radar sector, and in power electronics, for example in vehicle electronics, transmission and engine control. However, thermally demanding applications are often limited by relatively poor thermal conductivity of the material, which typically has a thermal conductivity of 2 W/m K. For the cooling of active semiconductor components, which are generally part of such LTCC modules as surface-mounted components, simple mounting of the LTCC substrate on a heat sink is inadequate. In particular, it is inadequate for an LTCC substrate to be soldered or adhesively attached to a heat sink, as described in J. Schulz-Harder et al.: “Micro channel water cooled power modules”, pages 1 to 6, PCIM 2000 Nuremberg.
An LTCC ceramic is compatible with silver metallization in the standard process. A customary solution for LTCC substrates is therefore the integration of thermal vias. These are vertical plated-through connections filled with silver-filled conductive paste and serve primarily for heat removal. In this way, an average thermal conductivity of 20 W/m K can be achieved. In combination with silver-filled sheets, values of 90 W/m K and 150 W/m K are made possible in the vertical and horizontal directions, respectively. This is disclosed by M. A. Zampino et al.: “LTCC substrate with internal cooling channel and heat exchanger”, Proc. Internat. Symp. on Microelectronics 2003, Internat. Microelectronics and Packaging Society (IMAPS) Nov. 18-20, 2003, Boston, USA.
A further solution is the mounting of semiconductor ICs (integrated circuits) with high heat loss, for example power amplifiers, in clearances in the LTCC board directly on the heat sink.
Also known are solutions that are based on the integration of liquid-filled channels. In this case, the cooling takes place by convection of a liquid with high thermal capacity, for example water, as described in the aforementioned prior art according to J. Schulz-Harder et al.: “Micro channel water cooled power modules”, and furthermore in M. A. Zampino et al.: “Embedded heat pipes with MCM-C Technology”, Proc. NEPCON West 1998 Conference Vol. 2, Reed Exhibition: Norwalk, Conn. USA 1998, pages 777-785, Vol. 2, (Conf. Anaheim, USA, Mar. 1-5, 1998).
A solution on this basis does not use the thermal capacity of the cooling liquid for the heat transfer but the latent heat of a phase transition. This is described in the aforementioned prior art according to M. A. Zampino et is al.: “LTCC substrates with internal cooling channel and heat exchanger” and in W. K. Jones et al.: “Thermal management in low temperature cofire ceramic (LTCC) using high density thermal vias and micro heat pipes/spreaders”, Proc. Internat. Symp. on Microelectronics 2002, Internat. Microelectronics and Packaging Society (IMAPS), Mar. 10-13, 2002, Reno, USA. According to the prior art, the “heat pipes” explained there are used, for example, for the cooling of processors in compact computers, such as laptops for example.
Apart from these methods that are suitable for LTCC, the so-called direct copper bonding process is suitable and widely used for highly sintered aluminum oxide ceramic, in order to bond circuit carriers of sintered aluminum oxide directly to cooling foils of copper at approximately 1100° C. This is described in J. Schulz-Harder et al.: “Micro channel water cooled power modules” and J. Schulz-Harder et al.: “DBC substrate with integrated flat heat pipe”, EMPC 2005, The 15th European Microelectronics and Packaging Conference & Exhibition, Jun. 12-15, 2005, Bruges, Belgium.